This invention relates to a rotational moulding machine which defines a chamber which can be closed and heated to apply heat to a mould mounted upon a spindle arm within the chamber.
Examples of a machine of this type are shown in U.S. Pat. Nos. 4,767,299 and 4,738,815 both by the present applicant. Each of these patents shows a single chamber which is known as a clam shell arrangement including a base for resting on the ground, four upstanding side walls surrounding the base all terminating at a position approximately halfway up the chamber and a cover which includes a top portion and four side walls depending downwardly to meet the top of the side walls of the base portion. The cover can be pivoted upwardly to expose the interior of the chamber. A front door on the base can be pivoted downwardly to allow access by the operator to the interior of the chamber.
Generally the mould is mounted upon a spindle arm assembly carried by frame structure on either side of the housing with the arm extending into the housing between the base portion and the cover. The spindle arm assembly remains effectively permanently within the housing. A heating arrangement is provided for the chamber and in addition a cooling arrangement is provided for the chamber so that the mould can be filled by the operator entering the unit by the front door, can be rotated and heated to provide a curing action of the material in the mould, can be rotated and cooled and finally can be unloaded while the mould on the spindle arm remains within the chamber at all times.
This device has been very successful and it has become widely used. However in some cases the fact that the spindle arm is mounted in the chamber throughout the process makes it more difficult for the operator to gain access to the mould and for the mould to be positioned for automation of the process in which the loading and unloading are carried out without the necessity for human operation.